SQL Server 2008 :: Column Datatype Update Not Usable

I ran a db update script to update the datatype for a column from a tinyint to a smallint:

ALTER TABLE MyTable
ALTER COLUMN Age smallint

Then I ran another db update script to update the value in these 2 columns:

update MyTable
set Age = Age * 12,

However, the second db update script returns the following error:

Msg 220, Level 16, State 2, Line 1
Arithmetic overflow error for data type tinyint, value = 1440.
The statement has been terminated.

SSMS shows the column with the new data type of smallint. I even restarted SSMS but I still get the error above. 1440 is out of range for a tiny int but should be in range for a smallint. Both scripts need to be executed together in sequence by the release manager.